Optimizing MICR ink usage with multiple ink droplet sizes

1. A printing apparatus comprising: a processor; an electronic memory operatively connected to said processor, said electronic memory maintains a density and magnetic strength relationship table; an inkjet printhead operatively connected to said processor, said inkjet printhead prints test patches of magnetic ink having magnetic particles using different ink droplet sizes on print media; and a sensor positioned to optically scan said magnetic ink printed on said print media by said inkjet printhead, said sensor scans said test patches printed on said print media to determine densities of said test patches, said processor determines a table-based density that produces a selected magnetic strength by applying said selected magnetic strength to said density and magnetic strength relationship table stored in said electronic memory, said processor identifies a matching test patch as one of said test patches having a density that most closely matches said table-based density, said processor identifies a selected droplet size as one of said different ink droplet sizes used to print said matching test patch, and said processor controls said inkjet printhead to produce magnetic ink droplets of said selected droplet size when printing a print job for said selected magnetic strength.

2. The printing apparatus according to claim 1 , different types of said print media have different absorption and dispersal characteristics, and said test patches produce different densities of said magnetic ink based on said different absorption and dispersal characteristics.

3. The printing apparatus according to claim 1 , said processor identifies said matching test patch using only measurements from said sensor, and reference to said density and magnetic strength relationship table.

4. The printing apparatus according to claim 1 , said processor receives a print job calling for printing said magnetic ink on said print media using a fixed drop size, and said processor changes said fixed drop size when controlling said droplet sizes to maintain said selected magnetic strength.

5. The printing apparatus according to claim 1 , said magnetic ink printed on said print media by said inkjet printhead comprises test patches printed on a sacrificial sheet of said print media.

6. A printing apparatus comprising: a processor; an electronic memory operatively connected to said processor, said electronic memory is capable of storing an optical density and magnetic strength relationship table; a user interface operatively connected to said processor, said user interface is capable of displaying a magnetic strength option that is capable of receiving an identification of a selected magnetic strength; an inkjet printhead operatively connected to said processor, said inkjet printhead is capable of printing test patches of magnetic ink having magnetic particles using different ink droplet sizes on print media; and an optical densitometer positioned to optically scan said magnetic ink printed on said print media by said inkjet printhead, said optical densitometer is capable of optically scanning said test patches printed on said print media to determine optical densities of said test patches, said processor is capable of determining a table-based optical density that produces said selected magnetic strength by applying said selected magnetic strength to said optical density and magnetic strength relationship table stored in said electronic memory, and said processor is capable of identifying a matching test patch as one of said test patches having an optical density that most closely matches said table-based optical density, said processor is capable of identifying a selected droplet size as one of said different ink droplet sizes used to print said matching test patch, and said processor is capable of controlling said inkjet printhead to produce magnetic ink droplets of said selected droplet size when printing a print job for said selected magnetic strength.

7. The printing apparatus according to claim 6 , different types of said print media have different absorption and dispersal characteristics, and said test patches produce different densities of said magnetic ink based on said different absorption and dispersal characteristics.

8. The printing apparatus according to claim 6 , said processor is capable of identifying said matching test patch using only optical measurements from said optical densitometer, and reference to said optical density and magnetic strength relationship table.

9. The printing apparatus according to claim 6 , said processor is capable of receiving a print job calling for printing said magnetic ink on said print media using a fixed drop size, and said processor changes said fixed drop size when controlling said droplet sizes to maintain said selected magnetic strength.

10. The printing apparatus according to claim 6 , said magnetic ink printed on said print media by said inkjet printhead comprises test patches printed on a sacrificial sheet of said print media.

11. A method comprising: creating a density and magnetic strength relationship table that outputs magnetic strengths from inputs of densities of printed magnetic ink, and identification of media types used for printing; printing test patches of magnetic ink having magnetic particles using different ink droplet sizes on print media, using an inkjet printhead of a printing apparatus; optically scanning said test patches printed on said print media to determine densities of said test patches, using a sensor of said printing apparatus; determining, by a processor of said printing apparatus, a table-based density that produces a selected magnetic strength by applying said selected magnetic strength to said density and magnetic strength relationship table; identifying, by said processor, a matching test patch as one of said test patches having a density that most closely matches said table-based density; identifying, by said processor, a selected droplet size as one of said different ink droplet sizes used to print said matching test patch; and controlling said inkjet printhead to produce magnetic ink droplets of said selected droplet size when printing a print job for said selected magnetic strength.

12. The method according to claim 11 , different types of said print media have different absorption and dispersal characteristics, and said test patches produce different densities of said magnetic ink based on said different absorption and dispersal characteristics.

13. The method according to claim 11 , said identifying said matching test patch uses only measurements from said sensor, and reference to said density and magnetic strength relationship table.

14. The method according to claim 11 , further comprising receiving, into said processor, a print job calling for printing said magnetic ink on said print media using a fixed drop size, said controlling said droplet sizes to maintain said selected magnetic strength.

15. The method according to claim 11 , said printing magnetic ink comprises printing test patches printed on a sacrificial sheet of said print media.

16. A method comprising: creating an optical density and magnetic strength relationship table that outputs magnetic strengths from inputs of densities of printed magnetic ink, and identification of media types used for printing, based on empirical testing; storing said optical density and magnetic strength relationship table in an electronic memory of a printing apparatus; displaying, on a user interface of said printing apparatus a magnetic strength option that is capable of receiving an identification of a selected magnetic strength; automatically printing test patches of magnetic ink having magnetic particles using different ink droplet sizes on print media, using an inkjet printhead of said printing apparatus; automatically optically scanning said test patches printed on said print media to determine optical densities of said test patches, using an optical densitometer of said printing apparatus; automatically determining, by a processor of said printing apparatus, a table-based optical density that produces a selected magnetic strength by applying said selected magnetic strength to said optical density and magnetic strength relationship table stored in said electronic memory; automatically identifying, by said processor, a matching test patch as one of said test patches having an optical density that most closely matches said table-based optical density; automatically identifying, by said processor, a selected droplet size as one of said different ink droplet sizes used to print said matching test patch; and automatically controlling said inkjet printhead to produce magnetic ink droplets of said selected droplet size when printing a print job for said selected magnetic strength.

17. The method according to claim 16 , different types of said print media have different absorption and dispersal characteristics, and said test patches produce different densities of said magnetic ink based on said different absorption and dispersal characteristics.

18. The method according to claim 16 , said identifying said matching test patch uses only optical measurements from said optical densitometer, and reference to said optical density and magnetic strength relationship table.

19. The method according to claim 16 , further comprising receiving, into said processor, a print job calling for printing said magnetic ink on said print media using a fixed drop size, said controlling said droplet sizes to maintain said selected magnetic strength.

20. The method according to claim 16 , said printing magnetic ink comprises printing test patches printed on a sacrificial sheet of said print media.